Wall anchors are known in the art. Generally, wall anchors take the form of either a friction-fit anchor, which is hammered into the wall, or a self-tapping anchor, which is screwed into the wall. These wall anchors find particular use in mounting articles, such as pictures or the like, to the wall. Wall anchors of this type are typically used in walls made of a friable material. The wall anchors are usually comprised of either a metal alloy, such as zinc, or a rigid plastic.
The friction-fit wall anchor is hammered into a pre-drilled hole in the wall by an installer, and usually consists basically of a cylindrical body configured to accept an elongated threaded fastener, and a flange to prevent the anchor from completely entering the wall. The flange also serves as an area where the required hammering force may be applied by the installer. Once inserted into the wall, a threaded fastener is engaged in the cylindrical body which causes the anchor to expand radially. Consequently, the friction-fit anchor is held in place by friction between the wall and the anchor.
The self-tapping anchor is screwed into the wall by an installer. The installer, through the use of an insertion device such as a manual or powered Phillips-head screwdriver, is able to quickly and easily insert the self-tapping anchor into the wall. Self-tapping anchors are primarily comprised of three separate components: a drilling portion which drills or bores a hole into the friable material, a threaded portion, which has a thread on a supporting cylindrical body that engages the friable material, and a flange which prevents the anchor from completely entering the wall. The flange also accepts the insertion device so that, upon turning the self-tapping anchor with the insertion device, the engaged thread draws the self-tapping anchor into the wall and becomes firmly mounted therein.
Prior art wall anchors implement splines on the cylindrical body of the wall anchor. The splines are disposed on an interior surface of the cylindrical body, extend generally longitudinally with respect to the body and engage an elongated threaded fastener, such as a sheet metal screw (SMS). Use of the splines allows the threaded fastener to be more easily inserted into the wall anchor due to the small amount of contact surface area between the threaded fastener and the splines. Since the material comprising the fastener is typically harder than the material comprising the wall anchor, the splines will also allow the threaded fastener to tap into the splines, which provides secure mounting of the article to be mounted.
The wide variety of available fasteners can change in both length of the fastener and the diameter of the threaded portion of the fastener. Since an installer of the wall anchor described above may have a need for the wide variety of fasteners offered, the installer must have a corresponding wide variety of wall anchors to accommodate the varying thread diameters of the fasteners. This in turn means that a manufacturer of wall anchors must provide a wide variety of wall anchors. However, carrying around a variety of wall anchors is cumbersome to the installer. Also, providing the corresponding variety of wall anchors by the manufacturer is likewise burdensome. For example, a different die must be designed and manufactured for each size of fastener to be accommodated. The making of separate dies for different size fasteners is not only expensive to the manufacturer of the wall anchor, but also adds to the number of different parts that must be inventoried, tracked, and eventually sold by the manufacturer.
Thus, a need exists for a wall anchor which accommodates fasteners having varying thread diameters.